// mcaptcha.js

export class Mcaptcha {
  constructor(options) {
    this.options = options;
    this.fontSize = (options.height * 3) / 6;
    this.init();
    this.refresh();
  }
  init() {
    this.ctx = uni.createCanvasContext(this.options.el);
    this.ctx.setTextBaseline("middle");
    this.ctx.setFillStyle(this.randomColor(180, 240));
  }
  refresh() {
    var code = "";
    var txtArr = [
      "a",
      "b",
      "c",
      "d",
      "e",
      "f",
      "g",
      "h",
      "i",
      "j",
      "k",
      "l",
      "m",
      "n",
      "o",
      "p",
      "q",
      "r",
      "s",
      "t",
      "u",
      "v",
      "w",
      "x",
      "y",
      "z",
      "A",
      "B",
      "C",
      "D",
      "E",
      "F",
      "G",
      "H",
      "I",
      "J",
      "K",
      "L",
      "M",
      "N",
      "O",
      "P",
      "Q",
      "R",
      "S",
      "T",
      "U",
      "V",
      "W",
      "X",
      "Y",
      "Z",
      0,
      1,
      2,
      3,
      4,
      5,
      6,
      7,
      8,
      9,
    ];
    for (var i = 0; i < 4; i++) {
      code += txtArr[this.randomNum(0, txtArr.length)];
    }
    this.options.createCodeImg = code;
    let arr = (code + "").split("");
    if (arr.length === 0) {
      arr = ["e", "r", "r", "o", "r"];
    }
    let offsetLeft = (this.options.width * 0.6) / (arr.length - 1);
    let marginLeft = this.options.width * 0.2;
    arr.forEach((item, index) => {
      this.ctx.setFillStyle(this.randomColor(0, 180));
      let size = this.randomNum(24, this.fontSize);
      this.ctx.setFontSize(size);
      let dis = offsetLeft * index + marginLeft - size * 0.3;
      let deg = this.randomNum(-30, 30);
      this.ctx.translate(dis, this.options.height * 0.5);
      this.ctx.rotate((deg * Math.PI) / 180);
      this.ctx.fillText(item, 0, 0);
      this.ctx.rotate((-deg * Math.PI) / 180);
      this.ctx.translate(-dis, -this.options.height * 0.5);
    });
    for (var i = 0; i < 4; i++) {
      this.ctx.strokeStyle = this.randomColor(40, 180);
      this.ctx.beginPath();
      this.ctx.moveTo(
        this.randomNum(0, this.options.width),
        this.randomNum(0, this.options.height)
      );
      this.ctx.lineTo(
        this.randomNum(0, this.options.width),
        this.randomNum(0, this.options.height)
      );
      this.ctx.stroke();
    }
    for (var i = 0; i < this.options.width / 4; i++) {
      this.ctx.fillStyle = this.randomColor(0, 255);
      this.ctx.beginPath();
      this.ctx.arc(
        this.randomNum(0, this.options.width),
        this.randomNum(0, this.options.height),
        1,
        0,
        2 * Math.PI
      );
      this.ctx.fill();
    }
    this.ctx.draw();
  }
  validate(code) {
    var code = code.toLowerCase();
    var v_code = this.options.createCodeImg.toLowerCase();
    // console.log(code);
    // console.log(v_code.substring(v_code.length - 4));
    if (code == v_code.substring(v_code.length - 4)) {
      return true;
    } else {
      return false;
    }
  }
  randomNum(min, max) {
    return Math.floor(Math.random() * (max - min) + min);
  }
  randomColor(min, max) {
    let r = this.randomNum(min, max);
    let g = this.randomNum(min, max);
    let b = this.randomNum(min, max);
    return "rgb(" + r + "," + g + "," + b + ")";
  }
}
